Orthodontic brackets represent a principal component of all corrective orthodontic treatments devoted to improving a patient's occlusion. In conventional orthodontic treatments, an orthodontist or an assistant affixes brackets to the patient's teeth and engages an archwire into a slot of each bracket. The archwire applies corrective forces that coerce the teeth to move into correct positions. Traditional ligatures, such as small elastomeric O-rings or fine metal wires, are employed to retain the archwire within each bracket slot. Due to difficulties encountered in applying an individual ligature to each bracket, self-ligating orthodontic brackets have been developed that eliminate the need for ligatures by relying on a movable portion or member, such as a latch or slide, for captivating the archwire within the bracket slot.
Conventional orthodontic brackets for the first and second molar teeth typically include a bracket in the form of a buccal tube that provides an anchor for the archwire. The buccal tube is typically secured to a tooth or to a molar band, which is in turn cemented to the first or second molar teeth. A terminal end of a conventional archwire is then fitted into the tube to facilitate orthodontic treatment. In some orthodontic treatments, a severely rotated molar makes it difficult to insert the end of the archwire into both the first and second molar tubes. In these severely rotated cases, a convertible buccal tube is often used on the first molar tooth to overcome the difficulty encountered with conventional buccal tubes.
In some orthodontic treatments, however, it is undesirable to fix the archwire and prevent movement of the archwire, as is done when traditional ligatures secure the archwire to a convertible buccal tube. To overcome this limitation of current molar brackets it would be desirable to use self-ligating brackets on the first and/or second molars. Nevertheless, their use has heretofore presented some undesirable drawbacks. For instance, one problem in using self-ligating brackets on the molar teeth is that their size often creates occlusion problems between the bracket and teeth on the opposing jaw. As the upper and lower teeth are brought together, such as for example, during chewing, the upper teeth may contact the brackets on the lower molars and may break or dislodge the brackets therefrom.
Furthermore, under normal conditions the gingival-occlusal height of molar teeth provides a limited surface on which to mount an orthodontic bracket. Prior self-ligating brackets have slides that engage the bracket body from below and travel along guides in the bracket body that are substantially parallel to the gingival-occlusal plane. Moreover, when in an opened position, the bottom edge of the slide extends below the bracket body. Thus, if traditional self-ligating brackets were attached to the bottom molar teeth, the bottom edge of the slide would contact gum tissue (gingiva) causing patient discomfort. Moreover, because gingival interference with the slide would be significant, the slide could not be fully opened to accept an archwire thus defeating an advantage of self-ligating brackets.
Yet another problem often encountered with traditional direct bonded self-ligating brackets is with applying the brackets to teeth. To apply a self-ligating bracket to a tooth, a medical practitioner will use a tool, such as tweezers, to grasp the bracket and manipulate the bracket within the oral cavity. Traditional self-ligating brackets, however, typically do not provide convenient gripping points so that the medical practitioner may securely grasp the bracket. Consequently, it is difficult to manipulate the bracket within the oral cavity without the bracket disengaging from the tweezers and falling on the floor or in a patient's mouth. This problem would be exacerbated when attempting to apply self-ligating brackets to molar teeth at the rear of the oral cavity.
There is a need for a self-ligating orthodontic bracket attachable to molar teeth that overcomes these and other deficiencies of conventional self-ligating orthodontic brackets.